1. Field of the Invention
The present invention pertains to cleaning electrical contacts from traces of contaminants so that good contact can be made between electrically conducting surfaces. Particularly, it pertains to use of terpene hydrocarbons and ketone blends as an environmentally safer substitute for Freon 11 and Freon 13 for the cleaning of printed wiring circuit boards, etc.
2. Background Art
The electrical power industry has traditionally employed solvent based cleaning agents to remove traces of dirt and moisture from their equipment. In any electrical field it is very important that no contaminants remain behind on such contact surfaces because this can cause dangerous arcing and serious damage to both equipment and its operators. For this reason, for many years solvent based cleaners, such as 1,1,1 Trichloroethane have been utilized to perform such tasks. This material was frequently used because of its high dielectric strength and its very fast evaporation rate. However, because of its high toxicity and hazard to the environment, an alternative method is now deemed necessary. 1,1,1 Trichloroethane upon inhalation causes a drastic in drop blood pressure, can be the cause of unconsciousness and even death when inhaled in large amounts. This product is also known to cause damage to the kidneys, liver, spleen, and blood can occur when ingested.
On the other hand, Freon 11 and Freon 13 which are chlorofluorocarbons evaporate very quickly but are very destructive to the ozone layer of the atmosphere and thus are no longer considered acceptable because of their destructive effect on the environment.
Newly developed hydrochlorofluorocarbons liquids are ozone safe but contain chlorine and fluorine which are not safe to the water supplies and soil. For these reasons, as well as their extremely high cost, it makes them unacceptable for this use.
Many other solvents have also been tried as electrical contact cleaners and circuit board cleaners, such as isopropyl/acetone mixtures which are extremely flammable, and non-biodegradable thus making them unacceptable for use as a cleaning aid. Alcohols also may carry moisture into a system and cause corrosion problems. Alcohols also are not good at dissolving oils and thus do not clean well. Petroleum distillates such as mineral spirits do not evaporate quickly and in general are very flammable and therefore dangerous to use.